I suggest you instead of sending it to the cassandra directly, first write spitted data to the CLI compatible file which would contain commands like "set <cf>[<key>][<column>] = 'value';" and see if file has all the data you want, after that you can insert it into C* using ./bin/cassandra-cli --host <ip> --keyspace <your-ks> < <file-with-cli-formatted-data> and check if C* then would have all of your data using 'list' command.

If you ask me if that is difficult, then I would have to tell no, it's not. Because you can check the file selectively and after you have loaded it into cassandra using CLI you can use 'count' command to check the number of inserted rows and do a selective "get" by key to check if all required columns are present. There is no need to check whole dataset by hand, at the last step you can modify your script to parse csv file and do get operations from C*, validate returned values to make sure that all of the data is there.

I have to put this command "set <cf>[<key>][<column>] = 'value';" 1 million times right?? I wrote the script for injecting data using set but using set 1 million times I am finding difficult. Is there any alternate way to parse csv inside script??